A metal U-section power track has parallel side walls that laterally delimit a retaining channel and that carry respective dielectric support rails that each in turn carry a plurality of uninsulated, bare electrical conductors that are insulated from one another, parallel to one another in the rail longitudinal direction, opposite one another, and exposed in the retaining channel. A ground conductor is also exposed in the retaining channel, preferably on the floor of the power track.
A coupling for joining two such rails or for joining such a rail to a power source is typically formed essentially symmetrically with respect to a center transverse plane and has contacts for contacting the conductors of the power track and mechanical guide and stop elements with which the coupling may be inserted, with its insertion depth limited, into the end of a power track.
Power tracks of this type are known for instance from FIG. 3 of DE OS 22 50 738. These couplings can connect such power tracks to one another mechanically and electrically, the power tracks being placed for example coaxially with one another on a suitable surface. In conventional couplings, relatively complex resilient contacts are provided that also lead to wear of the plastic parts when cooperating with the insulating parts of the housing element surrounding the contacts, so that service life is limited.